From e08d953fcb0f8483f72c7b232494d421c22f2447 Mon Sep 17 00:00:00 2001
From: imi415 <imi415.public@gmail.com>
Date: Fri, 5 Nov 2021 02:28:27 +0800
Subject: [PATCH] Added GDEW042T2.

---
 CMakeLists.txt                                |   3 +-
 include/epd_common.h                          |   4 +-
 include/epd_panel_gdew042t2.h                 |  26 +++
 include/epd_panel_gdew042t2_lut.h             | 185 +++++++++++++++
 ..._wfh0420cz35.h => epd_panel_wfh0420cz35.h} |   5 +
 include/epd_private.h                         |   3 +
 src/epd_common.c                              |   2 +-
 src/epd_panel_gdew042t2.c                     | 220 ++++++++++++++++++
 ..._wfh0420cz35.c => epd_panel_wfh0420cz35.c} |  45 +++-
 9 files changed, 486 insertions(+), 7 deletions(-)
 create mode 100644 include/epd_panel_gdew042t2.h
 create mode 100644 include/epd_panel_gdew042t2_lut.h
 rename include/{epd_wfh0420cz35.h => epd_panel_wfh0420cz35.h} (71%)
 create mode 100644 src/epd_panel_gdew042t2.c
 rename src/{epd_wfh0420cz35.c => epd_panel_wfh0420cz35.c} (70%)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0065f6b..668462f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,7 +4,8 @@ project(epd-spi)
 
 set(EPD_SOURCES
     "src/epd_common.c"
-    "src/epd_wfh0420cz35.c"
+    "src/epd_panel_wfh0420cz35.c"
+    "src/epd_panel_gdew042t2.c"
 )
 
 set(EPD_INCLUDES
diff --git a/include/epd_common.h b/include/epd_common.h
index 44b28e8..b52aaf9 100644
--- a/include/epd_common.h
+++ b/include/epd_common.h
@@ -3,6 +3,7 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <string.h>
 
 typedef enum { EPD_OK = 0, EPD_FAIL } epd_ret_t;
 
@@ -21,7 +22,4 @@ typedef struct {
     uint32_t y_end;
 } epd_coord_t;
 
-#define EPD_ASSERT(x) if(!(x)) for(;;) { /* ABORT. */}
-#define EPD_ERROR_CHECK(x) if(x != EPD_OK) return EPD_FAIL
-
 #endif
\ No newline at end of file
diff --git a/include/epd_panel_gdew042t2.h b/include/epd_panel_gdew042t2.h
new file mode 100644
index 0000000..7159a2f
--- /dev/null
+++ b/include/epd_panel_gdew042t2.h
@@ -0,0 +1,26 @@
+#ifndef EPD_GDEW042T2_H
+#define EPD_GDEW042T2_H
+
+#include "epd_common.h"
+
+/**
+ * @brief This display module has UC8176 controller IC,
+ * with BW partial or 4 grayscale LUT.
+ *
+ */
+
+typedef enum {
+    EPD_GDEW042T2_MODE_GS      = 0U, /* Grayscale mode */
+    EPD_GDEW042T2_MODE_BW      = 1U, /* B/W mode */
+    EPD_GDEW042T2_MODE_BW_PART = 2U, /* B/W mode with partial flush */
+} epd_gdew042t2_mode_t;
+
+typedef struct {
+    void                *user_data;
+    epd_gdew042t2_mode_t mode;
+    epd_cb_t             cb;
+} epd_gdew042t2_t;
+
+epd_ret_t epd_gdew042t2_upload(epd_gdew042t2_t *epd, epd_coord_t *coord, uint8_t *data1, uint8_t *data2);
+
+#endif
\ No newline at end of file
diff --git a/include/epd_panel_gdew042t2_lut.h b/include/epd_panel_gdew042t2_lut.h
new file mode 100644
index 0000000..b2bc53b
--- /dev/null
+++ b/include/epd_panel_gdew042t2_lut.h
@@ -0,0 +1,185 @@
+#ifndef EPD_GDEW042T2_LUT_H
+#define EPD_GDEW042T2_LUT_H
+
+#include <stdint.h>
+
+/**
+ * @brief Note for LUTs:
+ * LUTs are stored in arrays at the following order:
+ * VCOM WW BW WB BB WW(??),
+ * VCOM LUT has 44 bytes, while others has 42 bytes.
+ *
+ */
+
+typedef struct {
+    uint8_t VCOM[44];
+    uint8_t WW[42];
+    uint8_t BW[42];
+    uint8_t WB[42];
+    uint8_t BB[42];
+} gdew042t2_lut_t;
+
+// LUT waveforms
+static gdew042t2_lut_t gdew042t2_lut[3] = {
+    {
+        // Grayscale
+        .VCOM =
+            {
+                0x00, 0x0A, 0x00, 0x00, 0x00, 0x01,              //
+                0x60, 0x14, 0x14, 0x00, 0x00, 0x01,              //
+                0x00, 0x14, 0x00, 0x00, 0x00, 0x01,              //
+                0x00, 0x13, 0x0A, 0x01, 0x00, 0x01,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .WW =
+            {
+                0x40, 0x0A, 0x00, 0x00, 0x00, 0x01,  //
+                0x90, 0x14, 0x14, 0x00, 0x00, 0x01,  //
+                0x10, 0x14, 0x0A, 0x00, 0x00, 0x01,  //
+                0xA0, 0x13, 0x01, 0x00, 0x00, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .BW =
+            {
+                0x40, 0x0A, 0x00, 0x00, 0x00, 0x01,  //
+                0x90, 0x14, 0x14, 0x00, 0x00, 0x01,  //
+                0x00, 0x14, 0x0A, 0x00, 0x00, 0x01,  //
+                0x99, 0x0C, 0x01, 0x03, 0x04, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .WB =
+            {
+                0x40, 0x0A, 0x00, 0x00, 0x00, 0x01,  //
+                0x90, 0x14, 0x14, 0x00, 0x00, 0x01,  //
+                0x00, 0x14, 0x0A, 0x00, 0x00, 0x01,  //
+                0x99, 0x0B, 0x04, 0x04, 0x01, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .BB =
+            {
+                0x80, 0x0A, 0x00, 0x00, 0x00, 0x01,  //
+                0x90, 0x14, 0x14, 0x00, 0x00, 0x01,  //
+                0x20, 0x14, 0x0A, 0x00, 0x00, 0x01,  //
+                0x50, 0x13, 0x01, 0x00, 0x00, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+    },
+    {
+        // BW
+        .VCOM =
+            {
+                0x00, 0x17, 0x00, 0x00, 0x00, 0x02,              //
+                0x00, 0x17, 0x17, 0x00, 0x00, 0x02,              //
+                0x00, 0x0A, 0x01, 0x00, 0x00, 0x01,              //
+                0x00, 0x0E, 0x0E, 0x00, 0x00, 0x02,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .WW =
+            {
+                0x40, 0x17, 0x00, 0x00, 0x00, 0x02,  //
+                0x90, 0x17, 0x17, 0x00, 0x00, 0x02,  //
+                0x40, 0x0A, 0x01, 0x00, 0x00, 0x01,  //
+                0xA0, 0x0E, 0x0E, 0x00, 0x00, 0x02,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .BW =
+            {
+                0x40, 0x17, 0x00, 0x00, 0x00, 0x02,  //
+                0x90, 0x17, 0x17, 0x00, 0x00, 0x02,  //
+                0x40, 0x0A, 0x01, 0x00, 0x00, 0x01,  //
+                0xA0, 0x0E, 0x0E, 0x00, 0x00, 0x02,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .WB =
+            {
+                0x80, 0x17, 0x00, 0x00, 0x00, 0x02,  //
+                0x90, 0x17, 0x17, 0x00, 0x00, 0x02,  //
+                0x80, 0x0A, 0x01, 0x00, 0x00, 0x01,  //
+                0x50, 0x0E, 0x0E, 0x00, 0x00, 0x02,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .BB =
+            {
+                0x80, 0x17, 0x00, 0x00, 0x00, 0x02,  //
+                0x90, 0x17, 0x17, 0x00, 0x00, 0x02,  //
+                0x80, 0x0A, 0x01, 0x00, 0x00, 0x01,  //
+                0x50, 0x0E, 0x0E, 0x00, 0x00, 0x02,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+    },
+    {
+        // BW Partial
+        .VCOM =
+            {
+                0x00, 0x19, 0x01, 0x00, 0x00, 0x01,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,              //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .WW =
+            {
+                0x00, 0x19, 0x01, 0x00, 0x00, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .BW =
+            {
+                0x80, 0x19, 0x01, 0x00, 0x00, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .WB =
+            {
+                0x40, 0x19, 0x01, 0x00, 0x00, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+        .BB =
+            {
+                0x00, 0x19, 0x01, 0x00, 0x00, 0x01,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  //
+            },
+    },
+};
+
+#endif
\ No newline at end of file
diff --git a/include/epd_wfh0420cz35.h b/include/epd_panel_wfh0420cz35.h
similarity index 71%
rename from include/epd_wfh0420cz35.h
rename to include/epd_panel_wfh0420cz35.h
index 82abfca..9543aa6 100644
--- a/include/epd_wfh0420cz35.h
+++ b/include/epd_panel_wfh0420cz35.h
@@ -3,6 +3,11 @@
 
 #include "epd_common.h"
 
+/**
+ * @brief This display module has UC8176 controller IC, with BWR LUT stored in OTP.
+ *
+ */
+
 typedef struct {
     void    *user_data;
     epd_cb_t cb;
diff --git a/include/epd_private.h b/include/epd_private.h
index 54188ca..d843ab2 100644
--- a/include/epd_private.h
+++ b/include/epd_private.h
@@ -3,6 +3,9 @@
 
 #include "epd_common.h"
 
+#define EPD_ASSERT(x) if(!(x)) for(;;) { /* ABORT. */}
+#define EPD_ERROR_CHECK(x) if(x != EPD_OK) return EPD_FAIL
+
 epd_ret_t epd_common_execute_sequence(epd_cb_t *cb, void *user_data, uint8_t *seq, uint32_t seq_len);
 
 #endif
\ No newline at end of file
diff --git a/src/epd_common.c b/src/epd_common.c
index fcad200..b1a54a4 100644
--- a/src/epd_common.c
+++ b/src/epd_common.c
@@ -1,4 +1,4 @@
-#include "epd_common.h"
+#include "epd_private.h"
 
 /**
  * @brief Execute command sequence.
diff --git a/src/epd_panel_gdew042t2.c b/src/epd_panel_gdew042t2.c
new file mode 100644
index 0000000..6d19b9e
--- /dev/null
+++ b/src/epd_panel_gdew042t2.c
@@ -0,0 +1,220 @@
+#include "epd_panel_gdew042t2.h"
+
+#include "epd_panel_gdew042t2_lut.h"
+#include "epd_private.h"
+
+#define DTM1 0x10
+#define DTM2 0x13
+
+static uint8_t epd_gdew042t2_init_sequence_bw[] = {
+    0x04, 0x01, 0x03, 0x00, 0x2B, 0x2B,  // PWR setting
+    0x03, 0x06, 0x17, 0x17, 0x17,        // Boost
+};
+
+static uint8_t epd_gdew042t2_init_sequence_gs[] = {
+    0x05, 0x01, 0x03, 0x00, 0x2B, 0x2B, 0x13,  // PWR setting
+    0x03, 0x06, 0x17, 0x17, 0x17,              // Boost
+};
+
+static uint8_t epd_gdew042t2_init_sequence_bw_2[] = {
+    0x02, 0x00, 0xBF, 0x0D,              // Panel settings
+    0x01, 0x30, 0x3C,                    // PLL
+    0x04, 0x61, 0x01, 0x90, 0x01, 0x2C,  // Resolution
+    0x01, 0x82, 0x28,                    // VCOM DC
+    0x01, 0x50, 0x97,                    // VCOM/Data Interval
+};
+
+static uint8_t epd_gdew042t2_init_sequence_gs_2[] = {
+    0x01, 0x00, 0x3F,                    // Panel settings
+    0x01, 0x30, 0x3C,                    // PLL
+    0x04, 0x61, 0x01, 0x90, 0x01, 0x2C,  // Resolution
+    0x01, 0x82, 0x12,                    // VCOM DC
+    0x01, 0x50, 0x97,                    // VCOM/Data Interval
+};
+
+static epd_ret_t epd_gdew042t2_write_lut(epd_gdew042t2_t *epd) {
+    uint8_t tx_buf[45];
+
+    tx_buf[0] = 0x20;  // Write VCOM LUT
+    memcpy(&tx_buf[1], gdew042t2_lut[epd->mode].VCOM, 44);
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 45));
+
+    tx_buf[0] = 0x21;  // Write WW LUT
+    memcpy(&tx_buf[1], gdew042t2_lut[epd->mode].WW, 42);
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 42));
+
+    tx_buf[0] = 0x22;  // Write BW LUT
+    memcpy(&tx_buf[1], gdew042t2_lut[epd->mode].BW, 42);
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 42));
+
+    tx_buf[0] = 0x23;  // Write WB LUT
+    memcpy(&tx_buf[1], gdew042t2_lut[epd->mode].WB, 42);
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 42));
+
+    tx_buf[0] = 0x24;  // Write BB LUT
+    memcpy(&tx_buf[1], gdew042t2_lut[epd->mode].BB, 42);
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 42));
+
+    if (epd->mode == EPD_GDEW042T2_MODE_GS) {
+        tx_buf[0] = 0x25;  // Write mysterious WW2 LUT
+        memcpy(&tx_buf[1], gdew042t2_lut[epd->mode].WW, 42);
+        EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 42));
+    }
+
+    return EPD_OK;
+}
+
+static epd_ret_t epd_gdew042t2_init(epd_gdew042t2_t *epd) {
+    EPD_ASSERT(epd);
+    EPD_ASSERT(epd->cb.reset_cb);
+    EPD_ASSERT(epd->cb.write_command_cb);
+    EPD_ASSERT(epd->cb.poll_busy_cb);
+
+    EPD_ERROR_CHECK(epd->cb.reset_cb(epd->user_data));
+
+    // Pre power-on settings
+    if (epd->mode != EPD_GDEW042T2_MODE_GS) {
+        EPD_ERROR_CHECK(epd_common_execute_sequence(&epd->cb, epd->user_data, epd_gdew042t2_init_sequence_bw,
+                                                    sizeof(epd_gdew042t2_init_sequence_bw)));
+    } else {
+        EPD_ERROR_CHECK(epd_common_execute_sequence(&epd->cb, epd->user_data, epd_gdew042t2_init_sequence_gs,
+                                                    sizeof(epd_gdew042t2_init_sequence_gs)));
+    }
+
+    // Issue power on command
+    uint8_t tx_buf[2] = {0x04, 0x00};
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 0x01));
+
+    EPD_ERROR_CHECK(epd->cb.poll_busy_cb(epd->user_data));
+
+    // Post power-on settings
+    if (epd->mode != EPD_GDEW042T2_MODE_GS) {
+        EPD_ERROR_CHECK(epd_common_execute_sequence(&epd->cb, epd->user_data, epd_gdew042t2_init_sequence_bw_2,
+                                                    sizeof(epd_gdew042t2_init_sequence_bw_2)));
+    } else {
+        EPD_ERROR_CHECK(epd_common_execute_sequence(&epd->cb, epd->user_data, epd_gdew042t2_init_sequence_gs_2,
+                                                    sizeof(epd_gdew042t2_init_sequence_gs_2)));
+    }
+
+    return EPD_OK;
+}
+
+/**
+ * @brief Enable partial mode for UC8176 IC
+ * and set partial mode window.
+ *
+ * @param epd pointer to epd_gdew042t2_t
+ * @param coord pointer to epd_coord_t
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
+static epd_ret_t epd_gdew042t2_partial(epd_gdew042t2_t *epd, epd_coord_t *coord) {
+    EPD_ASSERT(epd);
+    EPD_ASSERT(epd->cb.write_command_cb);
+
+    // Partial In
+    uint8_t tx_buf[10] = {0x91, 0x00};
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 1));
+
+    // Partial window
+    tx_buf[0] = 0x90;
+    tx_buf[1] = (coord->x_start >> 8U) & 0x01U;
+    tx_buf[2] = coord->x_start & 0xF8U;  // Bank number, last 3 LSBs must be zero.
+    tx_buf[3] = (coord->x_end >> 8U) & 0x01U;
+    tx_buf[4] = coord->x_end & 0xF8U;  // Same as above.
+    tx_buf[5] = (coord->y_start >> 8U) & 0x01U;
+    tx_buf[6] = coord->y_start & 0xFFU;
+    tx_buf[7] = (coord->y_end >> 8U) & 0x01U;
+    tx_buf[8] = coord->y_end & 0xFFU;
+    tx_buf[9] = 0x01;  // Only scan partial area.
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 10));
+
+    return EPD_OK;
+}
+
+/**
+ * @brief Issue UC8176 DTM1 or DTM2 command, with payload data and stop command.
+ *
+ * @param epd pointer to epd_gdew042t2_t
+ * @param dtm_num DTM1 or DTM2
+ * @param data payload pixel data
+ * @param len payload data length, calculated as bytes
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
+static epd_ret_t epd_gdew042t2_dtm(epd_gdew042t2_t *epd, uint8_t dtm_num, uint8_t *data, uint32_t len) {
+    EPD_ASSERT(epd);
+    EPD_ASSERT(epd->cb.write_command_cb);
+
+    uint8_t tx_buf[2] = {dtm_num};
+
+    // Issue DTM1 or DTM2 command
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 0x01));
+    // Send data
+    EPD_ERROR_CHECK(epd->cb.write_data_cb(epd->user_data, data, len));
+    // Issue DSP command.
+    tx_buf[0] = 0x11;
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 0x01));
+
+    return EPD_OK;
+}
+
+/**
+ * @brief Issue display update command and enter deep-sleep mode.
+ * Deep-sleep mode can only exits with a hardware reset.
+ * @param epd pointer to epd_gdew042t2_t
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
+static epd_ret_t epd_gdew042t2_update_and_sleep(epd_gdew042t2_t *epd) {
+    EPD_ASSERT(epd);
+    EPD_ASSERT(epd->cb.write_command_cb);
+    EPD_ASSERT(epd->cb.delay_cb);
+
+    // Issue DRF command
+    uint8_t tx_buf[2] = {0x12, 0x00};
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 0x01));
+
+    // Delay 100ms and wait for busy
+    EPD_ERROR_CHECK(epd->cb.delay_cb(epd->user_data, 100));
+    EPD_ERROR_CHECK(epd->cb.poll_busy_cb(epd->user_data));
+
+    // Issue POF command
+    tx_buf[0] = 0x02;
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 0x01));
+    EPD_ERROR_CHECK(epd->cb.poll_busy_cb(epd->user_data));
+
+    // Issue DSLP command
+    tx_buf[0] = 0x07;
+    tx_buf[1] = 0xA5;
+    EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 0x02));
+
+    return EPD_OK;
+}
+
+/**
+ * @brief Initialize display, upload frame buffer and refresh.
+ * Then goes to deep-sleep mode to conserve power.
+ * This is the only function needs to be called by the user.
+ *
+ * @param epd pointer to epd_gdew042t2_t
+ * @param coord pointer to epd_coord_t, x_start or x_end MUST be wrapped to 8 pixel boundaries.
+ * @param data1 bw data or old data array
+ * @param data2 bw data or new data array
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
+epd_ret_t epd_gdew042t2_upload(epd_gdew042t2_t *epd, epd_coord_t *coord, uint8_t *data1, uint8_t *data2) {
+    EPD_ERROR_CHECK(epd_gdew042t2_init(epd));
+    EPD_ERROR_CHECK(epd_gdew042t2_write_lut(epd));
+    EPD_ERROR_CHECK(epd_gdew042t2_partial(epd, coord));
+
+    uint8_t  bank_start = coord->x_start / 8;  // Wrap to bank
+    uint8_t  bank_end   = coord->x_end / 8;    // Wrap to bank
+    uint32_t tx_len     = (bank_end - bank_start + 1) * (coord->y_end - coord->y_start + 1);
+
+    if (epd->mode != EPD_GDEW042T2_MODE_BW) {
+        EPD_ERROR_CHECK(epd_gdew042t2_dtm(epd, DTM1, data1, tx_len));
+    }
+    EPD_ERROR_CHECK(epd_gdew042t2_dtm(epd, DTM2, data2, tx_len));
+
+    EPD_ERROR_CHECK(epd_gdew042t2_update_and_sleep(epd));
+
+    return EPD_OK;
+}
diff --git a/src/epd_wfh0420cz35.c b/src/epd_panel_wfh0420cz35.c
similarity index 70%
rename from src/epd_wfh0420cz35.c
rename to src/epd_panel_wfh0420cz35.c
index fc6bf39..7e6c0b3 100644
--- a/src/epd_wfh0420cz35.c
+++ b/src/epd_panel_wfh0420cz35.c
@@ -1,4 +1,4 @@
-#include "epd_wfh0420cz35.h"
+#include "epd_panel_wfh0420cz35.h"
 
 #include "epd_private.h"
 
@@ -9,6 +9,13 @@ static uint8_t epd_wfh0420_init_sequence[] = {
     0x03, 0x06, 0x17, 0x17, 0x17,
 };
 
+/**
+ * @brief This function initialize the driver IC and
+ * enable internal power supplies.
+ *
+ * @param epd pointer to epd_wfh0420_t
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
 static epd_ret_t epd_wfh0420_init(epd_wfh0420_t *epd) {
     EPD_ASSERT(epd);
     EPD_ASSERT(epd->cb.reset_cb);
@@ -34,6 +41,14 @@ static epd_ret_t epd_wfh0420_init(epd_wfh0420_t *epd) {
     return EPD_OK;
 }
 
+/**
+ * @brief Enable partial mode for UC8176 IC
+ * and set partial mode window.
+ *
+ * @param epd pointer to epd_wfh0420_t
+ * @param coord pointer to epd_coord_t
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
 static epd_ret_t epd_wfh0420_partial(epd_wfh0420_t *epd, epd_coord_t *coord) {
     EPD_ASSERT(epd);
     EPD_ASSERT(epd->cb.write_command_cb);
@@ -52,12 +67,21 @@ static epd_ret_t epd_wfh0420_partial(epd_wfh0420_t *epd, epd_coord_t *coord) {
     tx_buf[6] = coord->y_start & 0xFFU;
     tx_buf[7] = (coord->y_end >> 8U) & 0x01U;
     tx_buf[8] = coord->y_end & 0xFFU;
-    tx_buf[9] = 0x01; // Only scan partial area.
+    tx_buf[9] = 0x01;  // Only scan partial area.
     EPD_ERROR_CHECK(epd->cb.write_command_cb(epd->user_data, tx_buf, 10));
 
     return EPD_OK;
 }
 
+/**
+ * @brief Issue UC8176 DTM1 or DTM2 command, with payload data and stop command.
+ *
+ * @param epd pointer to epd_wfh0420_t
+ * @param dtm_num DTM1 or DTM2
+ * @param data payload pixel data
+ * @param len payload data length, calculated as bytes
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
 static epd_ret_t epd_wfh0420_dtm(epd_wfh0420_t *epd, uint8_t dtm_num, uint8_t *data, uint32_t len) {
     EPD_ASSERT(epd);
     EPD_ASSERT(epd->cb.write_command_cb);
@@ -75,6 +99,12 @@ static epd_ret_t epd_wfh0420_dtm(epd_wfh0420_t *epd, uint8_t dtm_num, uint8_t *d
     return EPD_OK;
 }
 
+/**
+ * @brief Issue display update command and enter deep-sleep mode.
+ * Deep-sleep mode can only exits with a hardware reset.
+ * @param epd pointer to epd_wfh0420_t
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
 static epd_ret_t epd_wfh0420_update_and_sleep(epd_wfh0420_t *epd) {
     EPD_ASSERT(epd);
     EPD_ASSERT(epd->cb.write_command_cb);
@@ -101,6 +131,17 @@ static epd_ret_t epd_wfh0420_update_and_sleep(epd_wfh0420_t *epd) {
     return EPD_OK;
 }
 
+/**
+ * @brief Initialize display, upload frame buffer and refresh.
+ * Then goes to deep-sleep mode to conserve power.
+ * This is the only function needs to be called by the user.
+ *
+ * @param epd pointer to epd_wfh0420_t
+ * @param coord pointer to epd_coord_t, x_start or x_end MUST be wrapped to 8 pixel boundaries.
+ * @param red_data red pixel data array, bit 0 for red, bit 1 for white
+ * @param bw_data black pixel data array, bit 0 for black, bit 1 for white
+ * @return epd_ret_t EPD_OK for success, EPD_FAIL for error.
+ */
 epd_ret_t epd_wfh0420_upload(epd_wfh0420_t *epd, epd_coord_t *coord, uint8_t *red_data, uint8_t *bw_data) {
     EPD_ERROR_CHECK(epd_wfh0420_init(epd));
     EPD_ERROR_CHECK(epd_wfh0420_partial(epd, coord));